Merge branch 'agp-patches' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied...

[karo-tx-linux.git] / arch / x86 / mm / ioremap.c

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 69f4981db80f3dcc5e02eb0dca2d062e22144d97..882328efc3dbab30920cfa041892f1e877be9a50 100644 (file)
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -42,6 +42,22 @@ int page_is_ram(unsigned long pagenr)
        unsigned long addr, end;
        int i;
 
+       /*
+        * A special case is the first 4Kb of memory;
+        * This is a BIOS owned area, not kernel ram, but generally
+        * not listed as such in the E820 table.
+        */
+       if (pagenr == 0)
+               return 0;
+
+       /*
+        * Second special case: Some BIOSen report the PC BIOS
+        * area (640->1Mb) as ram even though it is not.
+        */
+       if (pagenr >= (BIOS_BEGIN >> PAGE_SHIFT) &&
+                   pagenr < (BIOS_END >> PAGE_SHIFT))
+               return 0;
+
        for (i = 0; i < e820.nr_map; i++) {
                /*
                 * Not usable memory:
@@ -51,14 +67,6 @@ int page_is_ram(unsigned long pagenr)
                addr = (e820.map[i].addr + PAGE_SIZE-1) >> PAGE_SHIFT;
                end = (e820.map[i].addr + e820.map[i].size) >> PAGE_SHIFT;
 
-               /*
-                * Sanity check: Some BIOSen report areas as RAM that
-                * are not. Notably the 640->1Mb area, which is the
-                * PCI BIOS area.
-                */
-               if (addr >= (BIOS_BEGIN >> PAGE_SHIFT) &&
-                   end < (BIOS_END >> PAGE_SHIFT))
-                       continue;
 
                if ((pagenr >= addr) && (pagenr < end))
                        return 1;